As a method for manufacturing a nitride semiconductor device, there is a technique for crystal-growing a nitride semiconductor layer such as gallium nitride (GaN) on a silicon (Si) substrate that is easily processable. When the nitride semiconductor layer is crystal-grown on the Si substrate, the nitride semiconductor layer is crystal-grown through a buffer layer formed on the Si substrate. Further, after the nitride semiconductor layer is crystal-grown, a support substrate is bonded to an opposite side of the Si substrate of the nitride semiconductor layer, and a thin film of the nitride semiconductor layer is formed by removing the Si substrate. In such method for manufacturing the nitride semiconductor device, it is to be desired that a manufacturing yield is further improved.